Telematics units are now widely in use on vehicles to provide drivers and passengers with various types of wireless assistance services. For example, roadside assistance, which historically involved a disabled vehicle and a physical visit to the vehicle by a serviceman, can now in many instances be provided remotely via wireless telecommunication with the vehicle through existing cellular network facilities. Thus, a telephone call to a call center can be used to electronically unlock doors where the keys have inadvertently been locked inside. Also, navigation and emergency assistance services can be obtained by voice communication with an advisor at the call center. Monitoring of vehicle operating conditions by the call center is also possible via the telematics unit. For example, an air bag deployment event can be automatically reported to the call center where it triggers a return call to the vehicle from a live advisor to determine if emergency services are needed. However, the services and capabilities of the telematics unit are characteristically limited to the technology and capabilities that exist at the time of design. Aside from software updates that address functionality and limited hardware adjustments, the traditional telematics unit is not upgradeable with respect to the network access device that enables the wireless assistance services. Consequently, the telematics unit becomes outdated and incompatible with emerging wireless and cellular technologies.